Several types of manually operated and foot operated devices have been developed for actuating parking brakes of automotive vehicles. Manually operated or foot operated devices have included the use of brake actuating levers in conjunction with a torsion spring for holding the lever in the brake setting position wherein the torsion spring is releasable to release the parking brake.
One such device is disclosed in U.S. Pat. No. 3,236,120 issued Feb. 22, 1966 in the name of Fender and assigned to Universal American Corporation. The patent discloses a method and assembly for controlling a parking brake mechanism of an automotive vehicle wherein the brake mechanism is held in the brake setting position by frictional engagement between a torsion spring and a drum which fits over the gear or pinion of the brake setting mechanism. The brake setting mechanism may be reliably held in brake setting position by the torsion spring and released with minimum of effort by the vehicle operator. The torsion spring is normally stressed to frictionally engage and grip the gear to hold the brakes in set position and includes a distal end which is actuated to flex the spring with a minimum of effort to release the spring from frictional engagement with the member and thereby release the parking brake mechanism. A vacuum mechanism is connected to the distal end to provide power release of the torsion spring. Power release is accomplished by engine vacuum wherein a valve is connected to the vehicle transmission whereby its movement actuates the valve. U.S. Pat. No. 3,236,121 issued Feb. 22, 1966 in the name of Gdowik and U.S. Pat. No. 3,315,538 issued Apr. 25, 1967 in the name of Fender, both assigned to Universal American Corporation, disclose similar brake assemblies utilizing a vacuum.
The problem with the use of a vacuum mechanism is that such is sensitive to changes in atmospheric pressure, and also tend to have a short life due to wear. Furthermore, it is difficult to utilize a source of vacuum with smaller engines.